E91 Gearbox fails under pressure

chiefrocka · 01-24-2020, 01:06 PM

Hello,

Tried to find a topic around here about this but no luck.
This has happened already three times to me.
When staying standstill and flooring it on "DS" mode, it goes fine first two gears (traction control on), traction control lights flash a bit, but on the third gear the gearbox just kind of goes into neutral, revs go to redline and then it takes 2-4 seconds for gearbox to pick back up and it starts shifting up. While in "neutral", the car is completely powerless.
It doesnt happen everytime, and all the times it has happened the car has been warmed up and at the operating temperature.
No error codes.
2010 E91 320D, 226k km (about 140k miles)

Meeni · 01-24-2020, 01:13 PM

You have a problem with hydraulics in the transmission. Can be because trans oil level is too low, a failed gasket inside the transmission that prevents oil pressure from building up ($50+pan/filter and oil change), a failed solenoid ($100 + afore cost), or a worn clutch pack (that's bad). There should be codes stored in the onboard computer, even if you don't have a service light on the dashboard, given the severity of the symptoms you describe.

chiefrocka · 01-25-2020, 06:15 AM

Quote:

Originally Posted by Meeni

You have a problem with hydraulics in the transmission. Can be because trans oil level is too low, a failed gasket inside the transmission that prevents oil pressure from building up ($50+pan/filter and oil change), a failed solenoid ($100 + afore cost), or a worn clutch pack (that's bad). There should be codes stored in the onboard computer, even if you don't have a service light on the dashboard, given the severity of the symptoms you describe.

Hey! Thanks for your answer. I'll try to pull some codes tonight. It happens rarely, otherwise once the car warms up transmission works like a charm. It is a bit "jerky" when car is cold tho :/
I belive every gear has its own solenoid? The third gear works well otherwise, maybe the solenoid can act differently under pressure?
Thanks in advance

Edit: if thats the "onboard computer" you're thinking of, its good, no faults. Sometimes when cold I do get a "increased battery discharge", and Im sure i need to switch out the battery soon, but I dont think that battery plays any role in transmission, or does it?

Meeni · 01-25-2020, 10:22 PM

I am refering to reading BMW specific codes using INPA or ISTA (the service program that the dealer uses to read the onboard diagnostic computer). This can reveal more codes and diagnostics than what is reported to the end-user.

Good luck debugging!

nsjames · 01-26-2020, 08:28 PM

what your're experiencing is commonly called a shift flare.

basically it's slipping the clutch in the transmission because it can't apply enough hydraulic pressure to the servo.
that's either a fluid supply/pressure issue.
a solenoid leakage issue
or a servo leakage issue.

most likely.
it's possible the clutch is wasted, but very low probability.

we never got your drivetrain in the US, so I am completely unfamiliar with what auto trans you have, but that's the basics of shift flares in pretty much any auto.

01-24-2020, 01:06 PM	#1
chiefrocka New Member 5 Rep 5 Posts Drives: E91 320D LCI Join Date: Dec 2019 Location: Estonia iTrader: (0)	E91 Gearbox fails under pressure Hello, Tried to find a topic around here about this but no luck. This has happened already three times to me. When staying standstill and flooring it on "DS" mode, it goes fine first two gears (traction control on), traction control lights flash a bit, but on the third gear the gearbox just kind of goes into neutral, revs go to redline and then it takes 2-4 seconds for gearbox to pick back up and it starts shifting up. While in "neutral", the car is completely powerless. It doesnt happen everytime, and all the times it has happened the car has been warmed up and at the operating temperature. No error codes. 2010 E91 320D, 226k km (about 140k miles)
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01-24-2020, 01:13 PM	#2
Meeni Gateropode 329 Rep 2,848 Posts Drives: BMW 330i 06 Join Date: Apr 2012 Location: TN iTrader: (0)	You have a problem with hydraulics in the transmission. Can be because trans oil level is too low, a failed gasket inside the transmission that prevents oil pressure from building up ($50+pan/filter and oil change), a failed solenoid ($100 + afore cost), or a worn clutch pack (that's bad). There should be codes stored in the onboard computer, even if you don't have a service light on the dashboard, given the severity of the symptoms you describe.
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01-25-2020, 10:22 PM	#4
Meeni Gateropode 329 Rep 2,848 Posts Drives: BMW 330i 06 Join Date: Apr 2012 Location: TN iTrader: (0)	I am refering to reading BMW specific codes using INPA or ISTA (the service program that the dealer uses to read the onboard diagnostic computer). This can reveal more codes and diagnostics than what is reported to the end-user. Good luck debugging!
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01-26-2020, 08:28 PM	#5
nsjames Brigadier General 2440 Rep 4,330 Posts Drives: 08 328xi Touring Join Date: May 2017 Location: ohio iTrader: (0)	what your're experiencing is commonly called a shift flare. basically it's slipping the clutch in the transmission because it can't apply enough hydraulic pressure to the servo. that's either a fluid supply/pressure issue. a solenoid leakage issue or a servo leakage issue. most likely. it's possible the clutch is wasted, but very low probability. we never got your drivetrain in the US, so I am completely unfamiliar with what auto trans you have, but that's the basics of shift flares in pretty much any auto.
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